AC Plasma Display Research Articles

Calculation of Ion Mobilities and their Effects on Gas Discharge of AC Plasma Display Cells

We have found that ion mobilities in a gas mixture greatly affect discharge characteristics of a plasma display cell. Therefore, correct ion mobilities are required to obtain meaningful simulation results on plasma display cells. Since plasma display panels use microdischarges in the Xe mixed gas to generate vacuum ultraviolet light to excite phosphor for visible light emission, the condition of the discharge gas mixtures is one of the main factors that determine luminous efficacy. Thus, intensive studies on the discharge gas mixture are essential to optimize it and the accurate determination of ion mobilities in it is necessary. We have discussed how to determine necessary values of ion mobilities in various discharge gas mixtures including the three-species He–Ne–Xe mixture. Calculated ion mobilities and their effect on the discharge of an AC plasma display cell have also been presented and discussed. We have revealed that the enhanced ion mobilities in the gas mixture resulting from adding He gas to the conventional Ne–Xe mixture play an important role in increasing the luminous efficacy of a plasma display cell sustained in the He–Ne–Xe mixture by decreasing the cathode fall potential.

26.1: Invited Paper: The Effect of Cell Geometry and Plasma Loss on the Luminous Efficiency in ac Plasma Display Panel

Enclosed barrier rib structure whose aspect ratio is 4:3 (horizontal to vertical) has shown an extraordinary high luminous efficiency increase compared to that of the conventional stripe cell structure (1:3 aspect ratio) when high Xe content gas or sustain auxiliary pulses are applied. The major reason we concluded through the numerical simulation to explain this phenomenon is the differences in the plasma loss to the barrier ribs. We also carried out experiments applying sustain auxiliary pulses to high Xe content test panels with green phosphor to obtain 6.7lm/W, 2800cd/m2 under continuous sustaining condition of 50kHz pulses.

32.4: Influence of H[sub 2] Addition to Xe-Ne Gas Mixtures for the Voltage Lowering of AC Plasma Display Panels

Discharge characteristics of Xe-Ne-H2 gas mixtures are investigated for the improvement of ac plasma display panel. Small amount of H2 addition to Xe-Ne gas mixtures results in lowering of the firing voltage. When H2 gas is mixed 0.01% of the total volume, the firing voltage is lowered by about 10%, and the aging time become bellow 1/10, while the luminous efficacy is almost unchanged compared to those of no H2 added gas mixtures. Surface modification of the MgO surface is suggested.

Discharging Characteristics of Green Cell Using MgO-Coated Zn2SiO4:Mn2+ Phosphor in Plasma Display Panel

The charging tendency of a Zn2SiO4:Mn2+ phosphor surface was modified in order to improve the discharging characteristics of green cell in an ac-plasma display panel (ac-PDP). The zinc silicate (Zn2SiO4:Mn2+) green-emitting phosphor was coated with magnesium oxide (MgO), which has a positive charge on the surface. After fabricating a green cell with MgO-coated Zn2SiO4:Mn2+, the electrical and optical properties were examined. It was found that the dynamic voltage margin could be increased while decreasing address time. This may be ascribed to a change in the charging tendency of Zn2SiO4:Mn2+ phosphor by the MgO coating, which makes stable wall-charge accumulation possible. When Zn2SiO4:Mn2+ phosphor was coated with 1.3 wt% MgO, the address time was decreased to 1.2 µs and the address voltage lowered to 25 V without any misfiring problem, compared with those of a noncoated Zn2SiO4:Mn2+ phosphor layer. The luminescence intensity of the green cell using the MgO-coated phosphor layer was also improved by 10%.

18.1: Invited Paper: Recent Developments of Delta Arranged Cell Configuration of AC Plasma Display Panels

AbstractA delta subpixel arranged AC‐PDP has some advantages over the trio subpixel one. The reason that the delta arrangement has not been applied to PDP is that conventional closed delta cells made the exhaust conductance small. However a new cell structure with improved exhaust performance has been developed. This paper explains the new rib structure, and delta arrangement PDP's advantages of high vertical resolution and high luminous efficiency.

P‐73: A New Gray‐scale Driving Method in an AC Plasma Display Panel

AbstractIn this paper, a new gray scale expression method that divides scan lines into multiple blocks is suggested. The proposed method can drive 16 sub‐fields per 1 TV field in the panel with XGA (1366×768) resolution. Because reset pulse is applied every 2 sub‐fields, both the contrast ratio and the dynamic voltage margin are sufficiently obtained in comparison with previous AWD (Address While Display) methods. In realizing 16 subfields, shortening the scan time in the erase address period was important. The X bias voltage in the erase address period affected the minimum address voltage but did not the delay time of address discharge. The delay time of address discharge was affected by the address voltage and the time interval between the last sustain discharge and the scanning time. We also evaluated the dynamic false contour. New method shows an improved image quality in horizontal moving, but discontinuous lines were observed at the boundaries of each block.

An efficiently revised sustain driver for AC plasma display

A new sustain driver employing a step-up function is presented to achieve the faster rise-time of sustain voltage, which Ls suitable for widely used address-and-display-period-separated (ADS) driving method, and most of all for cost saving. The proposed sustain driver can reduce the number of switching devices by 25 (%) compared to the prior approach improving the overall system efficiency about 10 (%). And brightness decrease problem resulted from the lack of the number of the sustain pulse can be solved without a limitation to sustain pulse width. Operational principle and its features are illustrated comparing with conventional approaches. The validity of the proposed sustain driver is verified through experiments using a prototype equipped with a 7.5 (inch) diagonal panel, which is operated at 200 (kHz) switching frequency.

New delta arranged cell configuration of AC plasma display “DIA‐PDP” for high luminous efficiency and high resolution

AbstractA new delta arranged cell‐configured AC plasma display (DIA‐PDP) was proposed, and a prototype 46‐inch diagonal panel was fabricated. The DIA‐PDP has two features. The first feature is an improved luminous efficiency. This is possible because nondischarge cells are formed in the panel and a black layer is formed on these cells. Since the light from the discharge cells does not reach the nondischarge cells, even if a black layer is provided on the nondischarge cells, the panel reflectance can be reduced without lowering the luminance. When compared under the condition of a constant set reflectivity, the luminous efficiency improves. A 33% improvement over the conventional ratio was verified for the 46‐inch panel. The second feature is improved vertical resolution. In the delta configuration, the subpixels are arranged at half the pitch of the scanning lines. By combining this configuration with an interlaced drive, the vertical resolution can be improved. To increase the size of a PDP using a lattice rib, we introduced a new rib forming technology and improved the exhaust conductance. Previously, the manufacturing steps increased to form the exhaust path in the lattice rib. In the new rib forming method, the exhaust conductance was successfully improved without increasing the number of manufacturing steps only for forming the crossing ribs in the nondischarge cells and by producing height differences caused by thermal shrinkage. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 87(2): 9–17, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.10169

Improvement of address discharge characteristics using asymmetric variable-width scan waveform in ac plasma display panel

A new asymmetric variable-width scan waveform is proposed to improve the characteristics of an address discharge, including a reduced address time and increased dynamic voltage margin, based on the formative and statistical time lags of an address discharge in an ac-plasma display panel (ac-PDP). The new asymmetric variable-width scan waveform has a progressively increasing scan pulsewidth that is wider than the address pulsewidth, thereby enabling stable wall charge accumulation under short address pulsewidth conditions. When adopting this new scan waveform, the address pulsewidth was reduced from 3.0 to 1.4 /spl mu/s and the address voltage lowered from 65 to 55 V without any misfiring problem at an address pulsewidth of 1.4 /spl mu/s.

Plasma display panel with Ne+ N/sub 2/ gas-mixture discharges

The discharge characteristics of Ne+N/sub 2/ gas-mixtures were investigated for possible use in an AC Plasma Display Panel (PDP). The firing voltage increased with an increase in the N/sub 2/ concentration. When using a near ultra violet excited phosphor, (Ba,Sr)/sub 2/ SiO/sub 4/:Eu, the luminous efficiency of Ne+10% N/sub 2/ gas-mixture discharges under 400 torr was about 20% better than when using the conventional phosphor. The UV intensity emitted from the gas discharges was found to increase with an increased N/sub 2/ concentration. Furthermore, the UV efficiency increased with an increase in the N/sub 2/ partial pressure at a low N/sub 2/ concentration, yet became saturated at a high N/sub 2/ concentration.

P‐56: Characteristics of Triangular Color pixel Arrangement TCA Structure AC Plasma Display Panel with Fine Pixel Pitches

AbstractThe static and dynamic characteristics of Triangular Color pixel Arrangement TCA structure Alternating Current Plasma Display Panel AC PDP were observed with the variation of the discharge gas. We observed the characteristic changes of operation voltages, brightness and luminous efficacy with required addressing time for TCA structure AC PDP. And the performance was verified in a 42‐in. diagonal WXGA PDP of 1024×768 format.

Improve the luminous efficiency of AC plasma display by high-frequency driving on address electrodes

A novel high-frequency driving scheme was proposed in this paper to improve the luminous efficiency of a plasma display. High-frequency oscillating waveform was applied to the address electrodes of the conventional three-electrodes AC-type plasma display panel during the sustaining period. More vacuum ultraviolet rays were generated by the high-frequency waveform so that the luminance and luminous efficiency could be enhanced. From experiments on an 8.5-in panel, the luminance was improved and the luminous efficiency was enhanced more than 40%.

Fabrication of the Diffusion Barrier for Bus Electrode of Plasma Display by Electroless Ni-B Plating

【In this study, we have investigated the availability of the electroless Ni-B plating for a diffusion barrier of the bus electrode. The Ni-B layer of 1 $\beta$ : thick was electroless deposited on the electroplated Cu bus electrode for AC plasma display. The layer was to encapsulate Cu bus electrode to prevent from its oxidation and to serve as a diffusion barrier against Cu contamination of the transparent dielectric layer in AC plasma display. The microstructure of the as-plated barrier layer was made of an amorphous phase and the structure was converted to crystalline at about 30 $0^{\circ}C$ . The concentration of boron was about 5∼6 wt.% in the electroless Ni-B deposit regardless of DMAB concentration. The electroless Ni-B deposit was coated on the surface of the electroplated Cu bus electrode uniformly. And the electroless Ni-B plating was found to be an appropriate process to form the diffusion barrier.】

P‐61: Discharge Characteristics of Ne+N2 Gas‐Mixture in an AC Plasma Display Panel

AbstractWe investigated discharge characteristics of Ne+N2 gas‐mixture for the possibility of being used in an AC Plasma Display Panel. The firing and the minimum sustain voltage increase with increase of N2 concentration. The luminous efficiency of Ne+N2 gas‐mixture with 300∼360 nm wavelength ultra violet excited phosphor[(Ba, Sr)2SiO4: Eu] relatively increases with increase of N2 concentration.

P‐63: Self‐Erasing Discharge Using Short Address Pulse During Sustain Period in AC Plasma Display Panel

AbstractIn this paper, a new driving scheme is proposed to improve the luminous efficiency using a self‐erasing discharge during a sustain‐period in an AC PDP. The self‐erasing discharge is produced between successive sustain pulses by simultaneously applying the short address pulses at the falling edge of the sustain pulses, thereby resulting in improving the luminous efficiency without reducing the luminance. It is found that this new driving scheme can improve the luminous efficiency by 37.5 % and the luminance by 3.5 %, when compared with the conventional driving scheme of an AC PDP.

Pulsed voltage-fed sustain circuit for AC plasma display drive

A new sustain circuit for an AC plasma display drive is proposed. The proposed circuit uses the instantaneous peak current flowing through the inductor during the charging and discharging of a plasma display panel, to recover most of the energy lost by the capacitive displacement current. This circuit can be realised with a small part-count, and gives the zero-voltage switching characteristics to all the switches even in the presence of a parasitic resistance, essential for the design of a sustain circuit for an AC plasma display. The capacitive displacement current and the required reactive power are greatly reduced in the proposed circuit. A comparative analysis and experimental results are presented to show the validity of the proposed energy recovery circuit.

An Energy Recovery Circuit for AC Plasma Display Panel with Serially Coupled Load Capacitance-SER1

The switching power loss due to the panel capacitance during sustain period in AC PDP driving system can be minimized by using the energy recovery circuits. We proposed a new energy recovery circuit, SER1 (Seoul national univ. Energy Recovery circuit 1st). The experimental results of its application to a 42-inch surface discharge type AC PDP showed superior performance of SER1 in energy recovery efficiency and low distortion voltage waveform. Energy recovery efficiency of SER1 was measured up to 92.3 %, and the power dissipation during the sustain period was reduced by 15.2 W in 2000 pulse/frame compared with serial LC resonance energy recovery circuit.

Discharge characteristics with respect to width of address electrode using three-dimensional analysis

A numerical analysis of the microdischarge in a surface-type AC plasma display cell has been made using the time-dependent, three-dimensional (3-D) fluid equations to understand the discharge characteristics. We investigate the breakdown dynamics with the width of address electrode and barrier ribs, because the typical 3-D parameters in an AC plasma display panel (AC PDP) model are the width of address electrode and the barrier ribs. It has been clarified that the width of address electrode has important role of the formation of discharge volume with the wall annihilation by barrier ribs and the accumulation of wall charges on the part of address electrode. The obtained time dependent spatial characteristics of an AC PDP discharge with the width of address electrode and the effect of wall annihilation by barrier ribs will help us to design the optimized AC PDP cells to get stable write and sustain discharges.

Intrinsic and Effective Secondary Electron Emission Coefficients in AC Plasma Display Panel

Ion-induced secondary electron emission from the MgO protecting layer of an AC plasma display panel (AC-PDP) and the successive back-scattering of secondary electrons toward the cathode due to high gas pressure have been studied theoretically. A correlation between the intrinsic secondary electron emission coefficient (γi) and the MgO surface properties such as band gap energy and defect states in the band gap was found. The behavior of the effective secondary electron emission coefficient (γeff) of various ion species as a function of the reduced electric field (E/P) has also been investigated. These relationships can be applied to AC-PDP manufacturing in order to enhance the luminous efficiency and to reduce the breakdown voltage of AC-PDPs.

Luminous efficiency of AC Plasma Display Panels with MgO–TiO2

ABSTRACTIn order to improve both the operating voltage and the luminous efficiency of the protective layer for AC Plasma Display Panels, controlled amount of TiO2 was added to the pure MgO. The effect of the TiO2 addition on both the electrical properties (firing voltage & sustain voltage) and the luminous efficiency of the Mg2−2xTixO2 films deposited by e-beam evaporation was investigated. By addition of a proper amount of TiO2 to MgO, the dielectric constant of protective layer was increased to the 11, which has higher than that of bulk MgO. When the composition of Ti in the thin films was about 2.45at%, firing and sustain voltages were very low. With this composition, the luminous efficiency characteristics were much better than that of any other protective layer. When compared to that of the conventional MgO protective layer, the luminous efficiency showed an increase by 28%.